Skirt wrinkles

[Givenupgivingashit]

I've just started a new part time job for which I have to wear issued uniform (skirt, jacket and blouse). I've been wearing it for 3 days and my skirt already looks a wrinkled mess. It's a very slim fit and I do have a bit of a tummy which doesn't help. I can't get the next size because it would be too large on my waist. Nothing has been said but I'm a) worried that it doesn't look particularly smart (what are people's opinions on this?), and b) in people's experience is there anything I can do to reduce them

I get the same on tight fit similar skirts unless it is a stretchier fabric. It doesn't particularly bother me but I would iron before re-wearing although it only lasts until I next sit down.
A looser fit would have the same issue because of the type of fabric. You could try getting the next size up and adjust the width with a seamstress, but I feel it would still be the same as soon as you sit down.
If you could get a longer jacket, you might be able to disguise it better.

When you are about to sit at the squatting down stage smooth down your skirt from the back down to your back of knees so the fabric lays flat against the chair. and then as soon as you sit down, flatten the front of the skirt by pulling it down to the fabric is absolutely flat and straight over your legs. Crossing your legs will cause wrinkles. Imagine your palms are ironing the skirt, make it flat when you sit and don't lean things on your lap like bags or files as they cause wrinkles.
Maybe wearing a slip underneath either a half slip or full might make your skirt drape better.

If you're tempted to cross your legs at the knees, try cross at the ankles and tucking your feet slightly under the chair or to the side. All the lady like etiquette stuff that you can find on youtube on how to sit as a lady actually keep dresses and skirts from wrinkling so it's graceful, elegant and keeps your clothes looking neat and fresh.

This is hard but also be conscious of your posture when you sit down, sucking the stomach in and keeping back straight.

It never used to bother me when I was younger, always had them to some extent with school skirts and ones which I wore for jobs like waitressing and travel agent uniform.
I think it's because I'm in a more professional role now, plus I feel a bit fatter, so they're either more pronounced or I perceive them as such. I suppose I just worry that I look unprofessional.

I'm up and down a lot so tbh although it's good advice, in reality I'd forget! Do slips actually work? The skirt is already lined

if it's already lined then a slip won't be of help I don't think.
Sorry I don't know what to suggest, bumping for you hoping someone knows a trick for this.

Sorry it just occurred to me, what do other women do with your uniform at work? Are they also ending up wrinkled? If not could you see what they are doing?